What BMI doesn’t tell you about your health

What BMI doesn’t tell you about your health


These are my assistants, Coleman and Phil. They’re both around the same height, weight,
and consequently, they have the same Body Mass Index — or BMI. But if you split them open Damien Hirst style
or just compare the results of their body scans you can see a slight difference. Phil has more body fat than Coleman, and Coleman
has more muscle than Phil. Although BMI is a popular measure to assess
if a person’s weight might be putting them at risk for obesity-related diseases,
its results can be pretty misleading and less nuanced than we’d like. So the BMI is an index that looks at somebody’s body weight divided by their height. So the formula is the body weight in kilograms divided by the height in square meters. 18.5 and below is underweight, 18.5 to 24.9
is your healthy range, 25 to 29.9 is overweight, and a BMI over 30 is classified as obese. With the idea being that the taller somebody is,
the more they should weigh. Kinda weird how a single decimal point can
separate being overweight from being obese. The major problem with using BMI as a marker of health when it comes to body weight, because
it penalizes you if you have a lot of muscle and you’re healthier. Let’s use professional athlete Marshawn
Lynch as an example. He’s 5’11, 215 lbs, and his BMI is 30. He’d be categorized as obese. That is because BMI doesn’t distinguish muscle
from fat. We are really concentrating on how much
muscle does somebody have, because muscle it’s the metabolic engine it’s the thing that burns
calories and the more muscle you have the easier it is for you to stay at a lower and
more healthy body fat percentage not necessarily a BMI. In this way, BMI’s reliability as an indicator
of health breaks down for athletes like Lynch. There are several more variables that can
influence the interpretation of BMI. Things like age, gender, and ethnicity. While BMI is a useful health measure for a
large population study, for example, to compare relative obesity rates from state to state;
it becomes more problematic when you use it to determine an individual’s health. The body mass index was introduced in the
early 19th century. The guy who created the formula — I’m
so sorry, I’m gonna butcher his name, Lambert Adolphe Jacques Quetelet — wasn’t
even a physician. Quetelet was a Belgian mathematician. And his reason for creating the formula was
to study the “normal man”, not obesity. Its use shifted to study obesity because of
Ancel Keys. In 1972, Keys used the formula in his “Indices
of Relative Weight and Obesity” study, renamed the formula to body mass index, and
from there the “new” measure caught on among researchers. Over the years, its use in the health professional
field grew and it’s pretty much stuck around since. It’s easy to use, cheap, fast, and its right about 80% of the time. So even though BMI has stuck around for more than 200 years, it’s not the be-all and end-all indicator. There are others ways to assess to body
composition, and overall health. Hydrostatic weighing, or underwater weighing, is an option. Along with MRI scans, and waist-to-hip ratio. Medical tests like checking blood pressure, your glucose levels, resting metabolic rate, can further give a picture of overall health. I went to George Washington University, and lab director Todd Miller showed me another way, using dual-energy x-ray absorptiometry
or DEXA image. It measures total body composition, including fat mass, lean body mass, and bone density. So the green is the areas where the
body is very lean. The yellow areas of moderate fat. And the red areas of high fat. So this person was here July 3rd she
had 72 pounds of fat and 109 pounds of muscle. And in December 27th of this year she had
at thirty seven pounds of fat in 115 pounds of muscle. Using this chart you can see if this person stepped on a scale, they’d only see they lost 29 pounds. What the scale wouldn’t say is that they gained six pounds of muscles, and BMI wouldn’t say that either. So even if two people have similar BMIs, that one number will never truly give either of them the full picture of their overall wellbeing. BMI is an indirect measurement of one aspect of an individual’s health. So while it can be helpful, it shouldn’t be the only way to understand the human body.

100 Replies to “What BMI doesn’t tell you about your health

  1. Me(underweight):I have a regular workout (Calisthenics),I don't drink or eat alot of sweets,I always eat 2 banana's everyday.

    My classmate(Normal BMI):Who always drink soft drinks,who doesn't have a regular workout,and doesn't have proper diet

    Now who's healthier?

  2. So, one BMI calculator I was on said I was supposed to be 78 lbs. I am 12, 5'4, and 113 lbs. Annaoop-

  3. Who thinks that BMI is the ultimate indicator of good health? Like, who actually thinks it's 100% accurate? Nobody that has common sense. Of course it's not giving you your muscle composition. However, if you are 100 pounds overweight and look like you can't walk, then yeah, I would think the BMI is pretty accurate when it's says you're morbidly obese. Let's not sugar coat it here.

  4. I feel like 90% of all people already know that BMI only looks at total mass, not composition. Vox must've been short on ideas that week.

  5. If you are not lifting the BMI is a good indicator, so is realistically looking in the mirror to see how much chub you got.

  6. For my height (181 cm) healthy range, according to bmi index, is between 60.6 and 81.6 kg. If i wanted to weight 60.6 kg, I would have cut off one of my legs, if not both. 😀 My most optimal weight would be about 85 kg, and even then I am considered as overweight…

  7. and, you can have an eating disorder at any weight ; overweight, "healthy weight", and underweight.
    Most people with eating disorders have a BMI in the "healthy" range.

  8. BMI is correct 80% of the time, that's really good. we should take our BMI as a vague indicator of where we should be weight wise especially if you don't exercise much. It's also easy and you can do it at home.

  9. I have a slight feeling that someome in this video is trying to convince people that they are healthy. Its obviously just a lot of belly muscle and big quads.

  10. What you fail to mention is the creator of the BMI chart was a eugenicist and that alone is enough to tell you its all BS.

  11. I’m 6 seconds into the video and wanted to stop and say THANK YOU for being the only American who included weight in KILOGRAMS. Appreciated 😊

  12. We discussed BMI in my fundamentals last semester. It's accurate because 98% of the adult population doesn't exercise. Everyone saying "Well BMI doesn't show muscle!" Has never been to the gym

  13. Well duh, if you are muscley enough for it to give you a high enough weight to make it seem overweight then you know you super buff and not overweight

  14. Well, obviously! BMI is just a basic computation when you don't have any medical equipment to determine exact body composition.

  15. BMI is an useful way to measure our health,at least for weight management bcs it is right 80% as mentioned in the video.

  16. BMI is used in a clinical setting to classify patients and thereafter, make nutrition recommendations and prescriptions. It is not used to classify elite athlete. A single decimal point being the difference between overweight and obese? No, you have an entire range to get through before being obese and that doesn't translate to the raw weight increase you need to gain to be classified as obese.

  17. Bmi is wrong for people who workout and put on a lot of muscle.. I'm weight around 245 at 6' tall ..my bmi is over 32..

  18. You don’t have to be an elite athlete to be muscular, by the way. I don’t know why people are saying only elite athletes can have high BMI’s.

  19. There's a lot of people talking about professional athletes here, but I've been on an intensive workout lately, for the first time in my life, and I've gained almost 3 kg of muscle. That has raised my BMI significantly, and while I'm still in the range of normal BMI, I'm dangerously close to being considered overweight, when I'm the healthiest I've ever been. I even look thinner. It's not just professional athletes this applies to. It happens to everyone.

  20. Oh this is too good. You're not an NFL running back and that BMI is due to deposited adipose tissue. Glad I could clear things up for everyone.

  21. I started lifting weights when I was younger and use to be confused as to why I didn't lose as much weight when I did runs and boxing but at least now I understand.

  22. I dont really understand BMI. For instance mine is around 20. I'm 5'4 and 117. I'm to thin, have a chronic illness that has caused unheathy weightloss due to loss of appetite and so many food sensitivities , i eat around 1 and a half meals a day. to get to 18.5 which is underweight I'd have to lose 10 pounds making me 107, which I think could only be done if I was chronically anorexic.
    Theres no way that's right.

  23. Im 194.5 cm tall and apparently I should be 68 kg according to the BMI test. I weight 98kg and go to the gym 4 days a week. I'm overweight according to the test. Imagine if anyone over 194 cm was 68 kg. Would be a literal twig.

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